GB1421101A - Citcuit arrangement for processing signals for the adaptive control of machine tools - Google Patents

Abstract

1421101 Automatic control of vibration WERKZEUGMASCHINENKOMBINAT FRITZ HECKERT KARL MARX-STADT VEB 18 April 1974 [18 April 1973] 17008/74 Heading G3R Vibration of a machine tool is kept at a desired value by a system in which the output of a vibration sensor 1 (which may alternatively detect the resultant variations in force or torque) is filtered by a band stop filter 2 and a band pass filter 3, the band of each being that due to "self excited" vibration, i.e. resonances in the machine; thus, the frequencies which are not stopped by 2 are those produced by "external excitation", i.e. dependent on tool cutting conditions, and these are passed to a "peak value rectifier" 4 and thence to a comparator 5 where comparison with a reference value is continuously made. Any difference is applied through an inhibit gate 6 to an output 7 which adjusts feed speed, cutting depth or cutting speed. At the same time the resonant frequencies passed by 3 are passed to a second "peak value rectifier" 8 and thence to a threshold device 9 which passes the signals, if they exceed a pre-set level, to an OR gate 10 and second output 11 which adjusts, e.g. cutting depth (if not performed by 7) or the engagement width of the tool. The output at 7 is inhibited at 6 when there is an output at 11. The output at 7 is also applied to a threshold device 12 set at a lower limit of feed speed and a further threshold device 13 passes the signal from 4 if it exceeds the prescribed desired value. 12 and 13 are connected to an AND gate 14 which thus produces a signal if the "external excited" vibrations are still excessive when the feed speed is reduced to its allowable minimum, and this signal produces an adjustment via OR gate 10 and the output 11.